RE: [PATCH v6 13/14] platform/x86: wmi: create character devices when requested by drivers

[Mario.Limonciello]

> -----Original Message-----
> From: Greg KH [mailto:greg@xxxxxxxxx]
> Sent: Tuesday, October 10, 2017 8:58 AM
> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> Cc: dvhart@xxxxxxxxxxxxx; andy.shevchenko@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx; luto@xxxxxxxxxx;
> quasisec@xxxxxxxxxx; pali.rohar@xxxxxxxxx; rjw@xxxxxxxxxxxxx;
> mjg59@xxxxxxxxxx; hch@xxxxxx
> Subject: Re: [PATCH v6 13/14] platform/x86: wmi: create character devices when
> requested by drivers
> 
> On Tue, Oct 10, 2017 at 01:41:45PM +0000, Mario.Limonciello@xxxxxxxx wrote:
> > > -----Original Message-----
> > > From: Greg KH [mailto:greg@xxxxxxxxx]
> > > Sent: Tuesday, October 10, 2017 6:07 AM
> > > To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> > > Cc: dvhart@xxxxxxxxxxxxx; Andy Shevchenko
> <andy.shevchenko@xxxxxxxxx>;
> > > LKML <linux-kernel@xxxxxxxxxxxxxxx>; platform-driver-x86@xxxxxxxxxxxxxxx;
> > > Andy Lutomirski <luto@xxxxxxxxxx>; quasisec@xxxxxxxxxx;
> > > pali.rohar@xxxxxxxxx; rjw@xxxxxxxxxxxxx; mjg59@xxxxxxxxxx; hch@xxxxxx
> > > Subject: Re: [PATCH v6 13/14] platform/x86: wmi: create character devices
> when
> > > requested by drivers
> > >
> > > On Mon, Oct 09, 2017 at 05:51:51PM -0500, Mario Limonciello wrote:
> > > > --- /dev/null
> > > > +++ b/include/uapi/linux/wmi.h
> > > > @@ -0,0 +1,19 @@
> > > > +/*
> > > > + *  User API methods for ACPI-WMI mapping driver
> > > > + *
> > > > + *  Copyright (C) 2017 Dell, Inc.
> > > > + *
> > > > + *  This program is free software; you can redistribute it and/or modify
> > > > + *  it under the terms of the GNU General Public License version 2 as
> > > > + *  published by the Free Software Foundation.
> > > > + */
> > > > +#ifndef _UAPI_LINUX_WMI_H
> > > > +#define _UAPI_LINUX_WMI_H
> > > > +
> > > > +#define WMI_IOC 'W'
> > > > +#define WMI_IO(instance)		_IO(WMI_IOC, instance)
> > > > +#define WMI_IOR(instance, type)		_IOR(WMI_IOC, instance,
> type)
> > > > +#define WMI_IOW(instance, type)		_IOW(WMI_IOC,
> instance, type)
> > > > +#define WMI_IOWR(instance, type)	_IOWR(WMI_IOC, instance, type)
> > >
> > > Are these really needed in a uapi .h file?  Who needs them?  And why not
> > > just use a "normal" ioctl macro in your individual driver .h file?  Do
> > > these really help?
> > >
> > Since this is setting precedent that WMI drivers will use the IOC 'W' and the
> WMI
> > bus driver will dispatch calls to the proper drivers, I think they make sense to
> include.
> 
> But who will use those macros?  Those drivers?
> 
> As the individual drivers have to define the correct "instance, type",
> this seems like a header file that is wrapping things unnecessarily.
> Why not just put all of the needed WMI ioctls in a single file, one for
> all of the drivers?  No need to have special per-driver ioctl .h files,
> right?
> 
Sounds good to me.  I'll reshuffle.